 |
||
 |
 |
 |
 |
||
 |
||
 |
||
 |
||
 |
||
 |
||
 |
||
 |
||
 |
||
|
FAQ & TROUBLESHOOTING Dissecting the Micro Mosquito Helicopter: Exposed and Explained by Seth Fogie, Jan 5, 2007 - informit.com Remote control helicopters have always been complex and expensive, at least until the Micro Mosquito by Interactive Toy Concepts flew onto the stage. Now, for less than $70, you too can own the world’s smallest, lightest, and most stable helicopter. In this article, we are going to examine this miniature device and explain how it works, plus expose its guts for your viewing pleasure. How Does a Normal Helicopter Fly?The helicopter is one of the most complex and difficult airborne vehicles you can operate. This is because the helicopter has the unique quality of being able to move in three-dimensional space, hover, and rotate in place. To accomplish this, the operator must maintain a focused, constant interaction with the controls using both hands and feet, or it will crash. To put this in perspective, a car really only has two controls that an operator needs to worry about—the steering wheel and the gas and brake pedals. These controls can be easily managed with one foot and one hand. On the other hand, a helicopter requires the operator to use his or her left foot, right foot, and both hands at all times; if the operator’s attention waivers for even a few seconds, the results could be disastrous. While the controls of the helicopter are complex, they only represent the intricate mechanical design that allows this vehicle to fly. In short, the helicopter must be able to maintain a delicate balance of "lift" and "thrust" to keep it moving through the air. The lift is created by spinning the helicopter’s blade on a rotor, which then "lifts" the helicopter into the air. NOTE Note that we say lift here, not blow. It is a very common misconception that a helicopter is blown into the air by pushing air away from the blade. In reality, a net vacuum is created on top of the helicopter blade, which then sucks, or lifts, the blade—and subsequently the helicopter—into the air. Another unique aspect about how a helicopter flies is that once it lifts off the ground, the body of the helicopter will have a nature inclination to start to spin. This is a natural reaction that is a result of the torque that is created by the force of the moving blades. You can experience this same type of torque if you try to spin in an office chair by twisting your body. When your body spins one way, the torque causes the chair to spin the opposite direction. To prevent this from occurring, conventional helicopters employ a tail rotor that is connected to the vehicle via a boom. This tail rotor is much like an airplane’s prop and is used to control the helicopter’s spin. In other words, it prevents uncontrollable spinning, but at the same time also allows the pilot to manually spin the helicopter in a desired direction. The last major functional aspect of a helicopter is to understand the significance of the angle of attack. Stop for a moment and think about how the helicopter goes up and down. Many assume that the speed of the rotor controls this particular aspect of how the helicopter flies—the faster the blades spin, the more lift is created. However, in the case of conventional helicopters, the physics of such a system would fail. Instead, each helicopter blade is dynamically tilted to increase or decrease the angle of attack—the steeper the angle of attack, or angle of the blade, the more lift is created. The "angle of attack" feature is also used to allow the helicopter to move left, right, forward, and backward. This is possible because each blade on a helicopter is able to have a different angle of attack via the use of swash plate assembly. Simply put, the plate assembly allows the blades to dynamically change their angle of attack as they rotate. For example, to move the helicopter forward, each blade will increase their angle of attack as it approaches the backside of the helicopter. This increases the lift on that one blade and raises the backend, thus moving the helicopter forward. As the blade continues on through the rotation, its angle of attack is reduced. 2. How Does the Micro Mosquito Fly? Now that you know how a normal helicopter is designed, you can appreciate the obstacles that the creators of the Micro Mosquito had to overcome. It is possible to purchase a remote control helicopter that includes most of the complexities of a real helicopter. However, these mechanical toys will cost you at least $1,000, which you will most certainly crash and destroy within a few hours. So, how does the Micro helicopter do it for a fraction of the cost? First, the Micro is not a true three-dimensional flier like a real helicopter. To properly represent a real copter, it would take six different controls (also known as six channels). The Micro only has three channels, but this is enough to emulate most of the functionality of a real helicopter. The first channel is directly tied to the speed of the blades, which increase or decrease the lift. As we discussed earlier, changing the speed of the rotor to control elevation is not a good idea for a conventional helicopter, but in the case of the Micro, it works perfectly. NOTE Keep the helicopter away from the ceiling and walls. The "lift" created by the spinning blades will not only pull a helicopter up into the air, but will also suck the helicopter to the large solid objects. Once this happens, it is very hard to break that suction without losing complete control of the Micro. The most obvious difference between a real helicopter and the radio-controlled (RC) version is that it has two blades instead of the normal one. What you may not notice about these blades is they are actually connected to two separate rotors, which are then connected to separate motors via the odd-looking gearing mechanism. Recall that a normal helicopter has only one main rotor, which creates torque and thus necessitates the tail rotor to keep the helicopter from spinning out of control. In the case of the Micro, the tail rotor blade is mounted horizontally, which means it can't be used to prevent the torque forces (see Figure 1). )
Figure 1 Helicopter and controller. Instead, Interactive Toy Concepts nullified the net torque by using two rotors that spin in opposite directions. The end result is that the torque from the one rotor is negated by the torque of the other rotor. Because the Micro is much more sensitive to things like battery power and normal wear and tear, the designers also included a small knob in the center of the controller to allow the user to manually tweak the speed of the lower rotor to match the speed of the upper rotor. This keeps the blades in sync, thus preventing the spin. While keeping the helicopter straight is amusing, it would be much more amusing if the toy could spin in the air while moving forward. This spinning functionality is handled by the second channel of the remote, which basically speeds up and slows down one main rotor motor, thus creating a slight torque that then causes the spinning effect. Moving the controller back to the center reduces the variance and stops the spin. This is the same channel that is used by the center knob to keep the Micro from spinning while hovering. So, how does the Micro move forward and backward? If you look at the tail rotor, you can see that it looks like a mini-blade and produces a small breeze when operated (see Figure 2). This is the third channel of the remote. It either sucks the backend down, which causes the helicopter to drift backward, or lifts the backend up, which causes the helicopter to slide forward. To help increase the forward motion of the Micro, you can add extra weights under each of the main motors (see Figure 3). This changes the center of balance for the entire device, and helps to tilt the helicopter forward at a deeper angle, which increases the forward momentum. )
Figure 2 Tail rotor. )
Figure 3 Extra weights for improved forward motion. In other words, the Micro creators emulated a conventional helicopter using some clever techniques. And because the design includes few parts that can break, the copter will survive crash after crash after crash (as the crash video illustrates). After a hard crash, you might have to realign the rotor gear with the motor head gear, as these often slip off. If you do break the main rotor assembly, RadioShack has replacement parts for your consumption. However, I have had my helicopter for about a month and am still using the same set of blades. 3. Dissecting the Micro From the outside, the Micro Mosquito is obviously a clever work of engineering. However, as the cliché goes, it is what’s on the inside that counts. So, to see if the internal design was as impressive as the outer design, I took it apart. Plus, I had a minor issue with the tail rotor that caused it to fail to operate in forward mode, so I actually had a valid reason for my disassembly adventure. This was easily fixed by repositioning the tail rotor wires (detailed later in this article). The following steps only require a small Phillips screwdriver: CAUTION These parts are fragile and small, so be sure to use care and store the parts in a safe location.
4. Tips on Flying the Micro Mosquito
Let’s discuss our flying experience a bit. As previously mentioned, we can maintain fairly good control over the device, and have gotten to the point where we can take off, fly around, and land on an area about the size of a pie pan. However, this took some practice because the Micro requires constant interaction and tweaking. So, here’s a few tips to help shorten your learning curve, as well as help you avoid some really bad crashes. The best way to familiarize yourself with the dynamics and controls of the helicopter is to practice hovering and landing. This might seem boring, but new users will have a difficult time at first just trying to hover the Micro, much less trying to land it without crashing. Once you are able to keep it up in the air, and land it softly, the next step is to understand the spinning trim knob in the center of the controller. While hovering, use this knob to keep the helicopter in place. Note that you will have to adjust the trim several times during a flight due to changes in battery strength and other external influences. Now you are ready to move the helicopter forward and backward. Use the controller to try to move the helicopter a few feet forward, and then resume hovering. One of the quirks of the Micro is that the blades can slowly tilt together, which causes the helicopter to sway around in the air until it crashes. You can avoid this by keeping the Micro moving forward in a controlled fashion. However, too much spinning while moving forward and up and down can cause the swaying action. Another issue you will quickly discover is that the Micro will stick to ceilings and walls, thanks to the vacuum of the lift. Try to fly the device in the middle of a room, away from solid objects and drafts, or you will find yourself trying to recover an out-of-control helicopter. I included a couple short movie clips of us flying around and landing (movie1.mpg), and even crashing (movie2.mpg). As you can see, the makers of the Micro really did create a durable indoor helicopter that is great fun to fly. 5. Is Your Micro Mosquito Busted? There have been a few reports of Micro Mosquito's not working as expected. If this is your case, check out the troubleshooting guide. In addition to this list, I noted another problem with the Micro that is not addressed by this list, which is the tail rotor not working. To fix this problem, you will have to disassemble the helicopter and ensure the thin motor wires leading to the boom are not touching each other or anything else. I noticed that after several hard crashes, these wires would sometimes move inside the body of the copter and short the tail motor out. This isn't too difficult to correct; however, it will require you to dissect the Mosquito. 6. Summary
The Micro Mosquito helicopter is well worth the $60 to $70 retail price. However, be forewarned that learning how to fly the Micro does take some time. Fortunately, it appears to be designed with the new pilot in mind and can crash as well as it flies. Plus, if you do manage to break the blades or another part, chances are you will be able to find replacement parts or fix it yourself as the device is not difficult to disassemble. I definitely recommend this toy to anyone who is fascinated by flight, RC devices, or just likes a challenge. I am giving at least three of these devices to friends and family for Christmas. Perhaps you should put a couple of these on your shopping list, too—one for a friend, and one for yourself!
Vist the RC Groups Forum for more resources and tips regarding our helicopters
FAQ’s
How much space do I need to fly?
HAPPY FLYING !
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||
)
)
)
)
)
)
)
)
)